The galaxy Messier 51 is perhaps better known by its nickname, the "Whirlpool Galaxy." Like the Milky Way, the Whirlpool is a spiral galaxy with spectacular arms of stars and dust. M51 is located about 30 million light years from Earth, and its face-on orientation to Earth gives us a perspective that we can never get of our own spiral galactic home. By studying the Whirlpool in X-ray light, astronomers can reveal things that would otherwise be invisible in other wavelengths. For example, nearly a million seconds of observing time from NASA's Chandra X-ray Observatory were used to create this new image. These data reveal over 400 X-ray sources within the galaxy. Most of these are so-called X-ray binary systems, in which a neutron star or black hole is in orbit with a star like our Sun. Understanding where these systems are, how they behave over time, and their role in the evolution of the galaxy in important is helping learn us more about other galaxies including our own.
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Earlier this year, astronomers discovered one of the closest supernovas in decades. Now, new data from NASA's Chandra X-ray Observatory has provided information on the environment of the star before it exploded, and insight into the possible cause of the explosion. On January 21, 2014, astronomers witnessed a supernova just days after it went off in the Messier 82, or M82, galaxy. Telescopes across the globe and in space turned their attention to study this newly exploded star. Astronomers quickly determined this supernova, dubbed SN 2014J, belongs to a class of explosions called "Type Ia" supernovas. These supernovas are used as cosmic distance-markers and played a key role in the discovery of the Universe's accelerated expansion, which has been attributed to the effects of dark energy.

While astronomers agree that Type Ia supernovas occur when a white dwarf star explodes, they are not sure exactly how this happens. For example, do these supernovas go off when the white dwarf pulls too much material from a companion star like the Sun, or when two white dwarf stars merge? Researchers used Chandra to look for clues. They took observations with Chandra about three weeks after 2014J and compared it with Chandra data taken prior to the explosion. They found, well, nothing.

Although it may sound counterintuitive, this non-detection of X-rays actually told astronomers quite a bit. Specifically, it showed that the environment around the star was relatively free of material before it exploded. This means that it's very unlikely that a messy transfer of material between the white dwarf and a companion star took place. Rather, whatever caused SN 2014J to explode cleared out the space around the star beforehand. This helps astronomers narrow down the possibilities and get closer to the answer of just what caused SN 2014J.
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Ultraluminous X-ray Sources, or ULXs, are unusual objects. They are rare and, as their name implies, give off enormous amounts of X-rays. Until now, astronomers thought that ULXs were powered by a system where a stellar mass black hole was in orbit around a neutron star or black hole. However, a study using data from NASA's NuSTAR and Chandra X-ray Observatory shows that this class of objects is more diverse than that. With NuSTAR, astronomers discovered regular variations, or pulsations, coming from a small region in the center of the galaxy M82, which is located about 11.4 million light years from Earth. The researchers then used Chandra, with its exceptionally keen vision in X-ray light, to pinpoint exactly which source was giving off these pulsations. This source is called M82X-2. It's hard to explain how a system with a black hole could generate the pulsations seen by NuSTAR. Because of this and other data, astronomers think that M82X-2 is the brightest pulsar ever seen. Pulsars are rapidly spinning neutron stars that sweep beams of radiation out like a lighthouse, and this is what would explain the pulsations of X-ray light seen in M82X-2. ULXs just became a little more unusual and intriguing to study.
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At this time of year, there are lots of gatherings often decorated with festive lights. When galaxies get together, there is also the chance of a spectacular light show. Take, for example, NGC 2207 and IC 2163. Located about 130 million light years from Earth in the constellation of Canis Major in the southern hemisphere, this pair of spiral galaxies is caught in a grazing encounter. This system has hosted three supernova explosions in the past 15 years, which is quite a few in such a short time.

This galactic pair has also produced one of the most bountiful collections of super bright X-ray lights known. These special objects - officially known as "ultraluminous X-ray sources" or ULXs - have been found using data from NASA's Chandra X-ray Observatory. As in our Milky Way galaxy, NGC 2207 and IC 2163 are sprinkled with many systems known as X-ray binaries, which consist of a star in a tight orbit around either a neutron star or a "stellar-mass" black hole. The strong gravity of the neutron star or black hole pulls matter from the companion star. As this matter falls toward the neutron star or black hole, it is heated to millions of degrees and generates X-rays. ULXs are far brighter in X-rays than most "normal" X-ray binaries. While the true nature of ULXs is still debated, they are likely an unusual type of X-ray binary. For example, some astronomers think that the black holes in some ULXs may be heavier than stellar mass black holes and could represent a hypothesized, but as yet unconfirmed, intermediate-mass category of black holes. Regardless of what they are, ULXs put on intriguing X-ray light displays no matter what the season.
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NGC 4258, also known as Messier 106, is a spiral galaxy like the Milky Way. This galaxy is famous, however, for something that our Galaxy doesn’t have – two extra spiral arms that glow in X-ray, optical, and radio light. These features, or anomalous arms, are not aligned with the plane of the galaxy, but instead intersect with it. The X-ray image from Chandra reveals huge bubbles of hot gas above and below the plane of the galaxy. These bubbles indicate that much of the gas that was originally in the disk of the galaxy has been heated to millions of degrees and ejected into the outer regions by the jets from the black hole. The ejection of gas from the disk by the jets has important implications for the fate of this galaxy. Researchers estimate that all of the remaining gas will be ejected within the next 300 million years -- very soon on cosmic time scales – unless it is somehow replenished. Without this gas, relatively few stars can form there. In fact, scientists estimate that that star formation in the central region of NGC 4258 is already being choked off, with stars forming at a rate ten times less than in the Milky Way galaxy.
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Galaxy clusters are enormous. In fact, they are the largest objects in the Universe held together by gravity. Just one galaxy cluster can contain hundreds or even thousands of individual galaxies. And what may be more interesting is that these galaxies make up just a fraction of the mass in these clusters. In addition to dark matter, the bulk of the mass in clusters actually comes from vast amounts of very thin gas. This gas is so hot that it only reveals itself in X-ray light. For many years, scientists have wondered why the hot gas doesn't cool and form lots of stars. With Chandra, astronomers have looked at many galaxy clusters, and in some, they found giant cavities carved out of the hot gas. They realized that the supermassive black holes at the centers of these clusters were pumping energy out into the gas through powerful jets. Now researchers have direct evidence for just how that energy keeps the gas in the entire galaxy cluster so hot. The answer may be turbulence. The same phenomenon that causes a bumpy airplane ride also prevents the hot gas in these galaxy clusters from ever settling down enough to cool. So while there are still many new things to learn about galaxy clusters, scientists may be finally homing in on the answer to one question that they have been asking for decades.
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The destructive results of a powerful supernova explosion are seen in a delicate tapestry of X-ray light in this new image. The remnant is called Puppis A, which could have been witnessed on Earth about 3,700 years ago and is about 10 light years across. This image is the most complete and detailed X-ray view of Puppis A ever obtained, made by combining a mosaic of different Chandra and XMM-Newton observations. In this image, low-energy X-rays are shown in red, medium-energy X-rays are in green and high energy X-rays are colored blue.
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Black holes seem like such mysterious and complicated objects. On one hand, they are, and astronomers have been studying them for decades to learn more. On the other, black holes are actually quite simple. By this, we mean that black holes are defined by just two simple characteristics: their mass and their spin. While astronomers have long been able to measure black hole masses very effectively, determining their spins has been much more difficult. A new result from researchers using data from NASA's Chandra X-ray Observatory and ESA's XMM-Newton takes a step in addressing the spin question. By a lucky alignment, the light from a quasar some 6 billion light years has been magnified and amplified due to an effect called gravitational lensing. This allowed researchers to get detailed information about the amount of X-rays seen at different energies. This, in turn, gave the researchers information about how fast the supermassive black hole at the center of the quasar is spinning. When combined with the spins from other black holes using more indirect methods, astronomers are beginning to better understand just how black holes grow over time across the Universe.
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One of the biggest mysteries in astrophysics today is figuring out where mysterious particles called neutrinos come from. Neutrinos are tiny particles that carry no charge and interact very weakly with electrons and protons. Unlike light or charged particles, neutrinos can emerge from deep within their sources and travel across the universe without being absorbed by intervening matter or, in the case of charged particles, deflected by magnetic fields.

The Earth is constantly bombarded with neutrinos from the sun. However, neutrinos from beyond the solar system can be millions or billions of times more energetic. Scientists have long been searching for the origin of these very energetic neutrinos.

Now scientists have a new clue in their hunt for the source of neutrinos. By analyzing data from three X-ray telescopes, including Chandra, researchers have found a connection between flares generated by the supermassive black hole at the center of the Milky Way and the arrival of high-energy neutrinos at a detector under the South Pole. In fact, the facility in Antarctica, called the IceCube Neutrino Observatory, saw one of these high-energy neutrinos less than three hours after Chandra detected the largest flare ever from the Milky Way's supermassive black hole. The Swift and NuSTAR X-ray telescopes also recorded flares that were later tied to IceCube neutrino detections.

While it's too early to say if the Milky Way's black hole is definitively generating high-energy neutrinos, the latest results are a promising lead for scientists to follow.
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This picture shows the very large, very distant and very gassy Coma Cluster. It's a giant cluster of over 1000 galaxies that are all bound together by gravity. If you take a close look, you can make out the yellow-white shapes of galaxies scattered across the picture. The pink blobs show arms of multi-million degree gas, hot enough to cook your lungs in half a breath.

All big clusters of galaxies contain this very hot gas. The gas sends out lots of powerful X-rays because it's so hot, and these are what we can see in pink here. You can't see X-rays with your eyes, so astronomers have coloured them in pink. This gas is actually a very helpful tool for us, because the amount of material in the cluster can be measured using just the temperature of the gas! The hotter the gas, the more material there is!

Our Galaxy is also part of a group of galaxies, called the Local Group. Our cluster is also filled with gas, but it's so spread out that we don't see it when we look into the night sky. And because the Local Group is much smaller than the Coma Cluster, the gas around our galaxy isn't nearly as hot.

The gas in this picture also tells another story. The shape of these pink clouds and how they are spread throughout the cluster give us clues into how the Coma Cluster has grown. They show us that smaller groups of galaxies and smaller galaxy clusters have crashed and combined over time. The final result is the colossal Coma Cluster we see today, one of the biggest structures in the entire Universe!
[Runtime: 02:07](NASA/CXC/April Jubett)